THE OOLOOIST 



91 



On Changes of Habit among 



Woodpeckers.* i 



BY SAMUEL CALVIN. ] 



I 



TT has loug been kaowu to uaturalists that 

 -*■ certain genera of Woodpeckers have 

 wholly or partly adopted habits quite incon- 

 sistent with those generally suggested when 

 we think of the group. 



Within the past two or throe years 1 have 

 frequently had the pleasure of observing the 

 Red-headed Woodpecker in tlie act of catch- 

 ing flies on the wiug. Seating itself on the 

 summit — not on the side — of some fence- 

 stake or other elevated perch, it watches, 

 as does the King Bird, for passing insects. ; 

 Having singled out the desired victim from 

 among many not worth catching, it darts 

 forward, catches it, and returns, usually to 

 the same perch, to wait for the next. This \ 

 any one may see repeated over and over a- 

 gain by the same individual, showing that 

 it is no mere chance departure from Wood- 

 ])eckeriau dignity into which the bird is in- 

 advertently betrayed, but is rather one of 

 the ordinary and settled practices resorted 

 to in procuring tbod. 



The movements in the air of this Wood- 

 pecker are very similar to those of the King 

 Bird ; it executes the gyrations and pecul- 

 iar gymnastics necessary to follow the dodg- 

 ing insect with great adroitness. 



What is the meaning of all this? The 

 barbed tongue, stout, straight bill, muscu- 

 lar neck, and structural adaptations for 

 climbing, all point tu a different mode of 

 life. None of them, certaiidy, cau be re- 

 garded as rendering the bird any special fit- 

 ness for fly-catching. It must be that the 

 struggle for life among bark-searching birds 

 has i-ecently — within the past two or three 

 geological epochs — become more severe, so 

 much so as to drive some of them to the a- 

 doption of other habits, quite regardless of 

 structural fitness. The Golden - winged 

 Woodpecker { Colaptes atiratus), as all 

 know, has been driven from the trees to feed 

 laigely on the ground. Its near relative 



*American Naturalist, Vol. XI., No. 8, p. 471. 



(Colaptes campestris), of some parts of 

 South America, frequents open plains, and. 

 according to the testimony of competent ob- 

 servers, is never seen on trees at all. 



As bearing upon these changes of habit, 

 and perhaps furnishing a suggestion in part 

 of their compelling cause, it is interesting to 

 note that quite a number of the perching 

 birds have settled into the questionable hab- 

 it of systematically poaching upon the spe- 

 cial domain of the Woodpecker. Among 

 the Warblers, even, we have in Iowa the 

 Black-and-white Creeper {Mniotilta varia)^ 

 that excels most Woodpeckers in ability to 

 scramble over and thoroughly search tlu' 

 bark of a tree. The whole family of Creep- 

 ers, the Certhias, — represented with us by 

 the little Brown Creeper, ( Certhia/amilia- 

 r/s), — is also able to compete successfully 

 with Woodpeckers on their own ground. 

 But perhaps the most expert of all the perch- 

 ers that have taken to clambering over trees 

 are the Nuthatches. A very common one is 

 the Sitfa carolinensis, which may be seen al- 

 most any day on trees in om* streets an<l 

 door-yards. Its nervous and rapid move- 

 ments, its slaty-colored back, and black 

 crown must be familiar to all. It moves 

 upward and downward with equal facility 

 and always head foremost ; the upper and 

 under side of a limb are explored with equal 

 ease ; rarely resting, it frisks up and down, 

 round and round, over and under, in and 

 out, finishing a tree and ready for the next 

 long before the average Woodpecker woulil 

 be able to collect himself and get fairly un- 

 der way. 



The habit of climbing is certainly an an- 

 cient one among Woodpeckers. All the 

 genera have the feet, tongue, bill, tail feath- 

 ers, etc., modified in substiintially the same 

 way, and this would point to an ancestor 

 that practiced their characteristic habits be- 

 fore the modern genera began to diverge. 

 On the other hand, we may fairly conclude 

 j that since climbing is rather exceptional a- 

 j mong perchers, the few groups that prac- 

 tice it have acquired it at a comparatively 

 recent date, and it is quite possible that 

 competition with climbing perchers may 



